Many factors, including environmental responsibility efforts and modern environmental regulations on engine exhaust emissions, have reduced the allowable acceptable levels of certain pollutants that enter the atmosphere following the combustion of fossil fuels. Increasingly, more stringent emission standards may require greater control over either or both the combustion of fuel and post combustion treatment of the exhaust. For example, the allowable levels of nitrogen oxides (NOx) and particulate matter have been greatly reduced over the last several years. Fuel injection timing and a quantity of fuel to be injected has been found to be an important factor in emission formation, along with other aspects such as exhaust gas recirculation (EGR), vane settings of variable geometry turbochargers (VGTs), intake manifold temperature, and intake valve timing.
An electronic engine control system thus may become very complicated in order to allow an engine to provide desirable performance, while also meeting required emissions limits. As the engine may be subjected to a variety of different operating tasks and operating conditions, a variety of engine operating parameters are controlled, such as fuel injection timing, fuel injection amount, fuel injection pressure, intake valve timing, exhaust valve timing, EGR valve settings, turbocharger settings, and the like. However, adjusting one engine parameter may counteract an adjustment made to another engine parameter, or may cause a greater change to engine operations than was intended when an adjustment is made to another engine parameter. It has been found that for a given engine operating condition, a number of engine operating parameters may be coordinated to a setpoint for the given engine operating condition, such that the setpoint allows the engine to generate a required power output, while also generating acceptable levels of NOx and particulate matter. A need exists for an engine control system that allows a plurality of setpoints for various engine operating conditions to be applied to an engine based on the operating conditions of the engine.